<template>
  <div class="qrcode">
    <div id="reader"></div>
  </div>
</template>

<script>
import {Html5Qrcode} from "html5-qrcode";

export default {
  data(){
    return {
      html5QrCode:null,
    }
  },
  created() {
    this.getCameras()
    navigator.mediaDevices.getUserMedia(constraints)
      .then(function (stream) {
        /* 使用这个 stream stream */
      })
      .catch(function (err) {
        /* 处理 error */
      });
  },
  beforeDestroy() {
    this.stop();
  },
  methods: {
    getCameras() {
      Html5Qrcode.getCameras()
        .then((devices) => {
          if (devices && devices.length) {
            this.html5QrCode = new Html5Qrcode("reader");
            this.start();
          }
        })
        .catch((err) => {
          // handle err
          this.html5QrCode = new Html5Qrcode("reader");
          this.error = "您需要授予相机访问权限"
          this.$emit("err", this.error)
        });
    },
    start() {
      //environment后置 user前置
      this.html5QrCode
        .start(
          {facingMode: "environment"},
          {
            fps: 2,
            qrbox: {width: 250, height: 250},
          },
          (decodedText, decodedResult) => {
            // this.$toast(decodedText);
            //decodedText扫描的结果
            this.$emit("ok", decodedText)
          }
        )
        .catch((err) => {
          this.$emit("err", err)
        });
    },
    stop() {
      this.html5QrCode.stop().then((ignore) => {
        // QR Code scanning is stopped.
        console.log("QR Code scanning stopped.");
      })
        .catch((err) => {
          // Stop failed, handle it.
          console.log("Unable to stop scanning.");
        });
    },
  }
}
</script>

<style lang="less" scoped>
.qrcode {
  position: relative;
  height: 100vh;
  width: 100vw;
  background: rgba( #000000,  0.48);
}

#reader {
  top: 50%;
  left: 0;
  transform: translateY(-50%);
}
</style>